NCERT Important Questions Class 10 Science
CBSE 2022-2023.
NCERT Book Extra Questions for Session 2022-2023
CBSE Board and UP Board Others state Board
NCERT book extra.
(a) State what happens when an acid reacts with a base? Name the reaction and give equation of the reaction involved. (b) Name one natural source of each of the following acids: (i) Citric acid (ii) Lactic acid. (iii) A student dropped a few pieces of marble in dilute Hydrochloric acid. The evolved gas passed through lime water. What change would be observed in lime water? Name the gas evolved.
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(a) When an acid reacts with a base, formation of salt and water takes place. This is called neutralisation reaction. For example, sodium hydroxide reacts with hydrochloric acid as under:
NaOH + HC1 ⟶ NaC1 + H₂O
(b) (i) Citric acid – Lemon
(ii) Lactic acid – Sour milk (curd)
(iii) Marble is calcium carbonate. Marble reacts with dilute hydrochloric acid to evolve carbon dioxide gas which when passed through lime water turns it milky. The reactions are as under:
CaCO₃ (s) + 2HCl (aq) ⟶CaC1₂ (aq) + CO₂ (g) + H₂O (1)
Ca(OH)₂ + CO₂ ⟶ CaCO₃ + H₂O
The gas evolved is carbon dioxide. Lime water will become milky.